Türk. entomol. derg., 2020, 44 (3): 385-397 ISSN 1010-6960 DOI: http://dx.doi.org/10.16970/entoted.740223 E-ISSN 2536-491X Original article (Orijinal araştırma) Identification, distribution and genetic diversity of Globodera rostochiensis (Wollenweber, 1923) Skarbilovich, 1959 (Tylenchida: Heteroderidae) populations in Turkey Globodera rostochiensis (Wollenweber, 1923) Skarbilovich, 1959 (Tylenchida: Heteroderidae)’in Türkiye popülasyonlarının tanımlanması, yaygınlık ve genetik çeşitliliği Ahmet ALTAŞ1 Emre EVLİCE2 Göksel ÖZER1 Abdelfattah DABABAT3 Mustafa İMREN1* Abstract The golden nematode, Globodera rostochiensis (Wollenweber, 1923) Skarbilovich, 1959 (Tylenchida: Heteroderidae) is one of the moSt economically important pestS of potato in the world. TeStS for thiS nematode are routinely performed for outbreakS and densitieS in potato growing areas. The morphological and molecular analySes for preciSe determination of the nematode are employed to establiSh appropriate management strategies. ThiS study showed that 96% of soil sampleS obtained from Bozdağ and Ödemiş DiStrictS of İzmir Province, during 2017 and 2018 potato growing seasons, were positive for G. rostochiensis. The mean number of cystS ranged from 0.01 to 3.70 cystS g-1 soil in the fieldS examined. The examination of the morphological and morphometric featureS of the second-stage juvenileS and cystS of the G. rostochiensis revealed slight differences among the populations obtained from Bozdağ and ÖdemiS. To asSesS the accuracy of the identification, partial sequenceS of riboSomal DNA for all populations were amplified, sequenced, and deposited in GenBank. The comparisonS of the sequenceS with thoSe of corresponding G. rostochiensis populations available in GenBank showed 99.89-100% nucleotide similarity. The reSultS of thiS study will help to better underStand the phySiology, ecology and biology of the nematode to quarantine thiS pest more effectively. Keywords: Globodera rostochiensis, ITS, İzmir, morphology, phylogeny Öz Altın nematod, Globodera rostochiensis (Wollenweber, 1923) Skarbilovich, 1959 (Tylenchida: Heteroderidae) dünyada ekonomik açıdan en önemli patates zararlılarından biriSidir. Genellikle patates yetiştirilen alanlarındaki dağılımları ve yoğunluklarını belirlemek amacıyla bu nematod için rutin olarak teStler gerçekleştirilmektedir. Morfolojik ve moleküler analizler bu nematodun kesin tanısını yapmak ve mücadele stratejilerini oluşturmak amacıyla kullanılmaktadır. Bu çalışma, İzmir İli’nin Bozdağ ve Ödemiş ilçelerinden 2017 ve 2018 yılları patates yetiştiriciliği sezonlarında alınan toprak örneklerinin %96'Sının G. rostochiensis ile enfekte olduğunu göstermiştir. Bulaşık alanlardaki ortalama kist sayısı, 0.01 ila 3.70 kist g-1 toprak arasında değişmiştir. Globodera rostochiensis'in ikinci dönem larva ve kistlerinin morfolojik ve morfometrik karakterlerinin incelenmeSi, Bozdağ ve Ödemiş’ten elde edilen popülasyonlarda arasındaki hafif farklılıkları ortaya koymuştur. Tanımlamanın doğruluğunu değerlendirmek için, tüm popülasyonlar için kısmi ribozomal DNA sekansları amplifiye edilmiş, sekanslanmış ve GenBank veritabanına kaydedilmiştir. Morfolojik ölçümler ve filogenetik analizler sonucunda Bozdağ ve Ödemiş'ten elde edilen popülasyonlar arasında küçük farklılıkların olduğu belirlenmiştir. SekanSların GenBank'ta mevcut karşılık gelen G. rostochiensis popülasyonlarıyla karşılaştırılması sonucunda nükleotid benzerliği %99.89-100 oranında görülmüştür. Bu çalışmanın sonuçları, bu zararlıyı daha etkili bir şekilde karantinaya almak için nematodun fizyolojiSini, ekolojiSini ve biyolojiSini daha iyi anlamaya yardımcı olacaktır. Anahtar sözcükler: Globodera rostochiensis, ITS, İzmir, morfoloji, filogenetik 1 Bolu Abant Izzet BaySal UniverSity, Faculty of Agriculture and Natural ScienceS, Department of Plant Protection, 14030, Bolu, Turkey 2 Plant Protection Central ReSearch InStitute, 06172, Yenimahalle, Ankara, Turkey 3 International Maize and Wheat Improvement Center (CIMMYT), 06511, Emek, Ankara, Turkey * CorreSponding author (Sorumlu yazar) e-mail: [email protected] Received (Alınış): 21.05.2020 Accepted (Kabul ediliş): 17.06.2020 PubliShed Online (Çevrimiçi Yayın Tarihi): 30.07.2020 385 Identification, diStribution and genetic diverSity of Globodera rostochiensis (Wollenweber, 1923) Skarbilovich, 1959 (Tylenchida: Heteroderidae) populations in Turkey Introduction Potato (Solanum tuberosum L. subsp. tuberosum) is the moSt cultivated tuber crop and an important staple food for over one billion people in the world. It rankS as the fourth for itS importance among food crops worldwide; following rice, wheat, and maize (FAOSTAT, 2020). Turkey is in the top ten potato producer countries in Europe with a production area of about 136 000 ha. Turkey annually produces about 34 t ha-1, which is still below the average yield potential and the reSt (about 40 t ha-1) is being imported from developed countries (FAOSTAT, 2020). Potato yield reduction is attributed to several biotic and abiotic factors, including pestS and pathogens (Subbotin et al., 2010). Plant-parasitic nematodes cause an annual loSS of 12% in potato production worldwide (Chitwood, 2003). In tropical and subtropical climateS, loSSeS associated with nematodes are estimated at 14.6% compared to 8.8% in temperate countries (SaSSer & Freckman, 1987). Among the top 10 plant-parasitic nematodes causing severe economic damage to crops around the world, six genera are reSulting yield reduction in potato (JoneS et al., 2013). AlSo, eight species from the seventeen quarantine nematodes declared by the European and Mediterranean Plant Protection Organization (EPPO, 2013) for the Euro-Mediterranean region, are major parasites of potato. DeSpite their considerable importance, nematodes of potato are not well studied in Turkey (Kepenekci, 2012). Potato cyst nematodes (PCN), Globodera spp. are obligate parasites reSulting in economic damage to potato around the world (Subbotin et al., 2010). TheSe nematodes are quarantined internationally and subjected to strict regulatory meaSureS (Fleming & PowerS, 1998). TheSe nematodes have already been found in 75 countries from Africa, Asia, Europe, North America, South America and Oceania (Ibrahim et al., 2000; Indarti et al., 2004; AndreS et al., 2006; Gitty & Tanha Maafi, 2010). SpecieS of PCN include golden potato cyst nematode, Globodera rostochiensis (Wollenweber, 1923) Skarbilovich, 1959, and pale potato cyst nematode, Globodera pallida Stone, 1973 (Tylenchida: Heteroderidae) are considered harmful quarantine organisms, described in European Union DirectiveS 2000/29/EC and 2009/7/EC and are also part of EPPO A2 List (quarantine species already present in the EPPO region, A2/125 and A2/124, respectively) (EPPO, 2013). TheSe species are regulated by the European Directive 2007/33/EC on the control of PCNs and are subject to stringent regulatory meaSureS when detected singly or in combination (EPPO, 2013). Specific identification of theSe species is juSt possible by observation of the female color at the appropriate stage of development, either a change from white to yellow in G. rostochiensis or prolonged white (slightly cream but no yellow phase) in G. pallida. The golden nematode, G. rostochiensis, is a regulated pathogen of potato and a threat to the potato induStry in several countries (Scurrah et al., 2005). EPPO has recognized the nematode as plant health quarantine species in the A2 list, which showS the local presence of the pathogen within the Euro- Mediterranean region. The loSSeS caused by the nematode mainly occurS in temperate regionS, in Mediterranean countries, where the host plantS are grown from mid-autumn to spring (Mugniéry, 1989). In Turkey, G. rostochiensis waS recorded for the first time in 1985 (Enneli & Öztürk, 1996), following the importing of seed potato from European countries (Baldwin & Mundo-Ocampo, 1991). The number of infeSted potato-producing areas in Turkey has significantly increaSed in the laSt few yearS (Kepenekci, 2012). Therefore, the crop protection services observed and reported theSe nematodes in many potato growing areas in the country (Ulutaş et al., 2012; Imren, 2018; ÖzarSlandan et al., 2019; Toktay et al., 2020). The pathogenic variability within potato cyst nematode, G. rostochiensis populations is determined by a set of differential host genotypes, and populations are classified into five pathotypes designated as Ro1 to Ro5 (Subbotin et al., 2010). The generation rateS of nematode populations on solanaceous plantS containing reSiStance genes can be used to differentiate pathotypes (Kort et al., 1977). The identification of nematode species as well as their pathotype provides crucial information to select appropriate and efficient management strategies (Ganguly & Rao, 2003). The morphological discrimination of Globodera spp. is conducted via microScopic examination of the structures of cystS and infective juvenileS (Golden, 386 Altaş et al., Türk. entomol. derg., 2020, 44 (3) 1990; Siddiqi, 2000; Subbotin et al., 2010). The increaSing number of species in the genus Globodera caused difficulties in obtaining sufficient criteria for the differentiation of species and requireS highly specialized taxonomiSts due to the minor morphological and morphometric differences within itS species (Subbotin et al., 1999, 2003). Molecular diagnostic techniques based on polymorphism of certain DNA fragments provide fundamental clues to overcome theSe taxonomic bottlenecks about morphological identification (SzalanSki et al., 1997;